Lucas to GM/Delco Alternator Swap
The electrical wiring is pretty straight forward. The Delco alternator has a two pin plug which connect the 'sense' and 'indicator' wires. The main battery connection is made via a bolt on terminal on the back of the alternator. The small brown, and small brown with yellow stripe wires go to the little two pin connector. The large brown wire goes to the bolt terminal. All the wiring color codes are identical (at least they are on my BGT and my Spitfire and my Midget)
The GM/Delco 'off the shelf' adapter on the left, and the stock Lucas connector on the right.
The 'gray' female bodied connector is cut off the GM/Delco cable and spliced in where
the Lucas connector was removed.
The photo above left, shows the adapter cable for the Delco alternator as purchased 'off-the-shelf' before cutting of the gray female bodied connector. It's sold as an extension cord as such. One male, one female connector, about 6" long. The white, male bodied connector is the one that plugs directly into the side of the alternator. Some of the Delco units even have the terminal #'s for the two pin connector embossed directly into the casting. Some don't. The designations for all the electrical connections are listed in the following table.
Function GM/Delco Cable Lucas Cable INDICATOR small connector Pin 1 (blk) small brown/yellow wire SENSE small connector Pin 2 (red) small brown wire OUTPUT bolt terminal large brown wire GROUND case of alternator via mount bolts
Pin one, on the alternator is the 'indicator'. This is wired to your dashboard mounted idiot light, via the small brown wire with the yellow tracer markings. The #2 wire is the battery sense wire and is connected to the small diameter brown wire. Depending on the adapter cable you buy, or connector you scrounged at the junk yard, the colors might be different than what I used. So you'll have to trace which wire is which and connect them appropriately. I used crimp lugs for simplicity to connect the small wires to the adapter cable. A ring terminal was crimped onto the large brown wire and it was bolted up to the stud on the back of the alternator.